[PATCH 3/3] drm/bridge: add pwdn-gpios support to the lvds-encoder

[Peter Rosin]

Optionally power down the LVDS-encoder when it is not in use.

Signed-off-by: Peter Rosin <p...@axentia.se>
---
 drivers/gpu/drm/bridge/lvds-encoder.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/gpu/drm/bridge/lvds-encoder.c 
b/drivers/gpu/drm/bridge/lvds-encoder.c
index 75b0d3f6e4de..43d584a6a6b9 100644
--- a/drivers/gpu/drm/bridge/lvds-encoder.c
+++ b/drivers/gpu/drm/bridge/lvds-encoder.c
@@ -11,11 +11,13 @@
 #include <drm/drm_bridge.h>
 #include <drm/drm_panel.h>
 
+#include <linux/gpio/consumer.h>
 #include <linux/of_graph.h>
 
 struct lvds_encoder {
        struct drm_bridge bridge;
        struct drm_bridge *panel_bridge;
+       struct gpio_desc *pwdn_gpio;
 };
 
 static int lvds_encoder_attach(struct drm_bridge *bridge)
@@ -28,8 +30,30 @@ static int lvds_encoder_attach(struct drm_bridge *bridge)
                                 bridge);
 }
 
+static void lvds_encoder_enable(struct drm_bridge *bridge)
+{
+       struct lvds_encoder *lvds_encoder = container_of(bridge,
+                                                        struct lvds_encoder,
+                                                        bridge);
+
+       if (lvds_encoder->pwdn_gpio)
+               gpiod_set_value_cansleep(lvds_encoder->pwdn_gpio, 0);
+}
+
+static void lvds_encoder_disable(struct drm_bridge *bridge)
+{
+       struct lvds_encoder *lvds_encoder = container_of(bridge,
+                                                        struct lvds_encoder,
+                                                        bridge);
+
+       if (lvds_encoder->pwdn_gpio)
+               gpiod_set_value_cansleep(lvds_encoder->pwdn_gpio, 1);
+}
+
 static struct drm_bridge_funcs funcs = {
        .attach = lvds_encoder_attach,
+       .enable = lvds_encoder_enable,
+       .disable = lvds_encoder_disable,
 };
 
 static int lvds_encoder_probe(struct platform_device *pdev)
@@ -45,6 +69,16 @@ static int lvds_encoder_probe(struct platform_device *pdev)
        if (!lvds_encoder)
                return -ENOMEM;
 
+       lvds_encoder->pwdn_gpio = devm_gpiod_get_optional(&pdev->dev, "pwdn",
+                                                         GPIOD_OUT_HIGH);
+       if (IS_ERR(lvds_encoder->pwdn_gpio)) {
+               int err = PTR_ERR(lvds_encoder->pwdn_gpio);
+
+               if (err != -EPROBE_DEFER)
+                       dev_err(&pdev->dev, "pwdn GPIO failure: %d\n", err);
+               return err;
+       }
+
        /* Locate the panel DT node. */
        port = of_graph_get_port_by_id(pdev->dev.of_node, 1);
        if (!port) {
-- 
2.11.0